What are the major factors that may influence the exchange rate?

What are the major factors that may influence the exchange rate?

a.international balance of payment. It has a direct bearing on the supply and demand of foreign exchange.
b.Inflation. It is closely related to the real value of the currency and the competitiveness of the commodity.
c.Interest rate. Under specific conditions, high interest rate will attract short term international fund, increasing the exchange rate of one’s own currency and vice versa.
The above factors may work alone or collectively.